"Mr. Trump just arrived in Chicago and after meeting with law enforcement has determined that for the safety of all of the tens of thousands of people that have gathered in and around the arena, tonight'srally will be postponed to another date," the campaign said in a statement. "Thank you very much for your attendance and please go in peace."

The goal of protesters in Chicago today is simple: shut down Donald Trump's speech.

Thousands have pledged online to attend a demonstration outside of the Republican frontrunner's rally at the University of Illinois's Chicago campus tonight, planning to outshine a man who has made a point of shaming his political opponents, particularly those who pop up at his rallies to make their feelings known. On Facebook, 11,000 people have said they will attend a Trump Rally Protest, and organizers have encouraged attendees to register for tickets to the candidate's event.

Protesters will be met with a crowd of Trump supporters, most of whom are expected to be coming in from downstate Illinois, according to the Cook County Republican Party Chairman Aaron Del Mar. "I don't know anyone from Chicago who is going," Del Mar told VICE.

The possible mixture of downstate Illinoisans—a group that is generally white and conservative compared to Chicago's diverse and liberal-leaning population—with black and Latino protesters could be volatile, which is probably why police, the university, and city officials are preparing for a chaotic night.

Many of the protesters will likely remain outside the venue, where University of Illinois has set up a stage for activists and politicians to host a counter-rally during Trump's speech. "I think there are a lot of people who would like to go inside but don't feel it's the safest place to be," said Ben Bobo, a 21-year-old college student who plans to attend the anti-Trump rally.

Bobo wouldn't disclose the number of people he believes will try to make it inside the pavilion, but hinted that their presence may be significant. "While he has his supporters here, there are still a significant amount of people in Chicago who feel Trump is not someone who represents us, is not someone who represents America," he said. "Hopefully, the media will make the story about the protest, not Trump's words."

Heading into the rally, tensions are already running high, exacerbated by a series of reports of violent confrontations between Trump supporters and protesters, as well as members of the media. In North Carolina, a Trump fan was arrested Thursday and charged with assault for allegedly sucker-punching a black protester at a rally there this week. Similar fights have broken out at Trump rallies in Massachusetts and Oklahoma in recent weeks. On Friday afternoon, before Trump made his way to Chicago, 12 demonstrators were detained outside of his campaign rally in St. Louis.

Trump's Chicago appearance seems particularly ripe for chaos, given the sheer number of protesters expected to turn out to disrupt Trump's event. Citing reports of violent clashes at Trump rallies, more than 300 faculty and staff members at the University of Illinois, Chicago signed an open letter asking the school to cancel Friday's event. "We are deeply distressed that this event threatens to create a hostile and physically dangerous environment to the students, staff, faculty and alumni who come out to express their opposition," the letter states.

Their fears are perhaps justified. In the lead up to the Chicago event, theories and rumors about who will show up to protest Trump's rally have swirled among the candidate's supporters online. School administrators are clearly concerned about the potential escalation, and sent out a mass email to students explaining where protests would be allowed, and informing the campus that the university was coordinating with multiple law enforcement agencies and the Secret Service on security matters.

The Chicago Police Department hasn't released specific security plans. CPD spokesman Anthony Guglielmi told VICE there would be "very visible police presence" at the event, but directed further questions to the Secret Service. The Secret Service did not immediately respond to a request for comment.

At this point, Bobo said, the protesters won't be at the Trump rally to change anyone's minds. The goal, he said, is simply to silence the GOP frontrunner, and co-opt the media spotlight from his presidential campaign. "We don't feel like allowing him to continue to make the same hurtful and racist comments," Bobo said.